The use of radiation to treat medical conditions comprises a known area of prior art endeavor. For example, radiation therapy comprises an important component of many treatment plans for reducing or eliminating unwanted tumors. Unfortunately, applied radiation does not inherently discriminate between unwanted structures and adjacent tissues, organs, or the like that are desired or even critical to continued survival of the patient. As a result, radiation is ordinarily applied in a carefully administered manner to at least attempt to restrict the radiation to a given target volume.
Many treatment plans provide for exposing the target volume to radiation from a number of different directions. Arc therapy, for example, comprises one such approach. In such a case it often becomes useful or necessary to also adjust various mechanical components (such as, for example, multi-leaf collimators) of the treatment system when moving the radiation source with respect to the target volume. A radiation-treatment plan therefore often provides information regarding useful or necessary adjustments to various mechanical components of the treatment system during such a treatment.
Such plans are often calculated using an iterative process. Beginning with some initial set of settings, a radiation-treatment planning apparatus iteratively adjusts one or more of those settings and assesses the relative worth of the adjusted plan. An iterative approach such as this is often referred to as “optimizing” the plan (where “optimizing” should not be confused with the idea of identifying an objectively “optimum” plan that is superior to all other possible plans). Optimizing such a plan can prove challenging as the overall computational requirements can be considerable. As one example in these regards, a candidate treatment plan often comprises a plurality of control points (pertaining, for example, to collimator leaf settings at each of a plurality of source angles in an arc therapy application setting).
More particularly, the radiation-treatment platform that will serve to administer the radiation treatment in accordance with the optimized plan typically has numerous corresponding physical limitations. For example, the radiation source will typically move no faster than some given speed during the treatment and the multi-leaf collimator used during that treatment can only change its aperture settings subject to some maximum speed. A treatment plan that fails to account for such physical characteristics can ultimately be unusable if the aperture settings from one position to the next are physically impossible to achieve.
In some application settings, the time required to work through such iterative calculations while accounting for the various physical limitations as pertain to the intended treatment system can result in vexing delays. These delays, in turn, can lead to expensive and undesirable equipment downtime, patient discomfort, and increased costs.
Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention. Certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. The terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.